ms12 to ms11 conversion is most likely related to attempts to export or some kind conversion between two different versions, namely from version 12 to version 11.
Unfortunately, NI Multisim is not backwards compatible, meaning you cannot save newer format to older one.
But some users report that you can export SPICE netlist from version 12 and import that to version 11, which will at least preserve the essence of the schematic.
This conversion entry was verified by us and conversion was flagged as wrong or not possible.
Usually this happens when the conversion would try to convert different types of data between each other, such as audio to image, or it is not possible because incompatibility between programs, caused by closed file formats, very limited support etc.
If you find entry that you feel is flagged as bad wrongly, please tell us in the discussion below with as much as information as possible so we can fix it.